Yes… But there are people who professionally do this. Worldbuilders. They are clearly material dependent.

Of course they are. World builders can only spend so long on one given project, and have to tie their work in with prior material, then on a sequel they get a chance to explain events in the time gap as well as expand on more bits.

Look at the Elder Scrolls series. A lot of the lore in Skyrim was written nearly 20 years before the release of that game. And Oblivion massively expanded on things introduced in Daggerfall